Neymar has extended his contract at Santos to 2014.
"I'm one of the fans, I love to play for Santos and the happiness of being in my country," Neymar said at a press conference at which he was flanked by his father and Santos president Luis Alvaro Ribeiro.
"Here is where I'm happy and here is where I want to stay. I've always said that happiness would play a significant role in my decision."
Asked about his future after the World Cup, Neymar insisted that he could not see beyond Santos.
"I do not see myself leaving Santos," he said. "I plan to stay here a long time."
Ribeiro believes Brazil will be "a happier country" knowing that Neymar is staying at one of its biggest clubs.
"Some months ago we started a fight seen by some as a dream," he said on Wednesday.
"Finally this morning we finished the negotiations with the father of Neymar.
"Through dialogue, built day after day, he understood the permanence of Neymar ahead of the 2014 World Cup would provide a service to the country.
"I think Brazil is now a happier country."